The invention relates to an endoscope, with a tubular shaft whose interior contains components, in particular lenses, spacers, diaphragms, prisms and filters of an optical system, said components being at least partially surrounded by a support piece made of shrunk material.
The invention also relates to a method for assembling components, in particular lenses, spacers, diaphragms and filters of an optical system in the interior of a tubular shaft of an endoscope, said components being surrounded by a support piece made of shrunk material.
Such an endoscope and such a method are known from document DE 197 32 991 C2.
In the method disclosed in the latter document, the shrinkable material is used to fix the components of the optical system in the tubular shaft. To do this, the components are introduced into a support piece made of shrinkable material at least partially surrounding said components, and this unit is then pushed into the tubular shaft. The dimensions are such that a small gap remains between the outside face of the support piece and the inside face of the tubular shaft. As the material shrinks, it expands slightly in the radial direction and fills the gap, so that in this way the unit is fixed on the inside face of the tubular shaft.
DE 39 12 720 C2 also discloses the use of a plastic shrinkable tube for positioning the elements of a relay lens system of an endoscope. The material is chosen such that it does not transmit light, i.e. is opaque. This is intended to ensure that light does not pass from the light guide into the area of the relay lens system or into the area of the objective lens and there cause reflections or glare. The lenses of the lens system can first be placed in a correct position. The shrinkable tube is then shrunk by application of heat so that it holds the lenses, without a lens fixture in the conventional sense being needed.
This construction is intended to make it possible to produce endoscopes extremely inexpensively, and provision is therefore also made to produce the lenses from plastic.
In the document DE 39 12 720 C2 mentioned earlier, the aim is to fix the expensive components of the optical system to the inside face of a metal tubular shaft by using the shrink properties of the material surrounding these components.
It is an object of the present invention is to further optimize an endoscope and a method for assembling components in such a way that, by using shrinkable materials, it is possible to fix the optical components relative to one another in a way which can also be checked.